1. Technical Field
The present invention relates to a method for manufacturing metal nanoparticles, more particularly, to a method for manufacturing which may synthesize highly concentrated nanoparticles having a small size and a uniform size distribution at low temperature without using an additional organic solvent or a reducing agent.
2. Description of the Related Art
There are two major methods for chemically synthesizing metal nanoparticles, namely a vapor phase process and a colloidal process. The colloidal process capable to synthesize uniform nanoparticles with low cost has been generally used because the vapor phase process using plasma and mechanical gas vaporization requires highly expensive equipments.
The method for manufacturing metal nanoparticles by the colloidal process includes a method for manufacturing hydrosol-formed metal nanoparticles by additional use of a reducing agent or a surfactant after dissociating a metallic compound in an aqueous system. As another method, a phase transfer method is the method for manufacturing metal nanoparticles which can be dispersed in a non-aqueous phase by transferring from an aqueous phase to a non-aqueous phase.
This method, however, provides a very low yield because it is limited by the concentration of the metal compound solution when the nanoparticles are synthesized. In other words, the metal nanoparticles having a uniform size distribution may be formed only when the concentration of the metal compound is 0.05 M or less. Therefore, it is not suitable for the mass production, because there is a limit on the yield of metal nanoparticles and more than 1 liter of a reactor is required to obtain metal nanoparticles having a uniform size distribution of several grams. Also, the use of the phase transfer agent is not desirable in the aspect of the cost.